Dark halos around neutron stars and gravitational waves

Nelson, Ann E.; Reddy, Sanjay; Zhou, Dake

doi:10.1088/1475-7516/2019/07/012

Cited by 104 publications

(148 citation statements)

References 67 publications

(89 reference statements)

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“…If we instead consider a neutron star (NS), we can constrain the type and strength of dark matter interactions via the requirements that the resultant neutron star heating is not too large [18][19][20][21][22], that the star does not accumulate so much dark matter that collapse to a black hole is triggered [23][24][25][26][27][28][29][30], and that the neutron star structure is not perturbed to the extent that the gravitational wave signatures from binary neutron star mergers are inconsistent with observations [31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Capture of leptophilic dark matter in neutron stars

Bell

Busoni

Robles

2019

J. Cosmol. Astropart. Phys.

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Dark matter particles will be captured in neutron stars if they undergo scattering interactions with nucleons or leptons. These collisions transfer the dark matter kinetic energy to the star, resulting in appreciable heating that is potentially observable by forthcoming infrared telescopes. While previous work considered scattering only on nucleons, neutron stars contain small abundances of other particle species, including electrons and muons. We perform a detailed analysis of the neutron star kinetic heating constraints on leptophilic dark matter. We also estimate the size of loop induced couplings to quarks, arising from the exchange of photons and Z bosons. Despite having relatively small lepton abundances, we find that an observation of an old, cold, neutron star would provide very strong limits on dark matter interactions with leptons, with the greatest reach arising from scattering off muons. The projected sensitivity is orders of magnitude more powerful than current dark matter-electron scattering bounds from terrestrial direct detection experiments.Neutron stars provide particularly powerful DM constraints, because their high density leads to efficient capture. Indeed, for DM-nucleon cross sections above a threshold value of order 10 −45 cm 2 , the capture probably saturates at the geometric limit, σ ∼ πR 2 * m n /M * , such that all dark matter incident on the star is captured. This conclusion holds irrespective of whether DM scattering interactions are spin independent (SI) or spin dependent (SD). Given that conventional direct detection experiments currently have sensitivity to DM-nucleon cross sections below 10 −45 cm 2 only in a limited DM mass range, and only for SI interactions, NS techniques are clearly very useful. Moreover, velocity or momentum dependent interactions are completely inaccessible to terrestrial direct detection experiments, being severely suppressed in the non-relativistic regime applicable for scattering on Earth. In comparison, DM particles are accelerated to quasi-relativistic velocities upon NS infall, effectively erasing such kinematic suppression.When dark matter is gravitationally captured by a NS, the kinetic energy transferred in the collisions heat up the star. The captured dark matter will then undergo a series of further collisions, eventually transferring almost all of its initial kinetic energy, to reach a state of thermal equilibrium with the star. As shown in Refs. [18,19] this can heat neutron stars up to 1700K. 1 Because old isolated neutron stars can cool to temperatures below 1000K, such heating (or its absence) can be used to place limits on the strength of dark matter interactions. 2 Importantly, this kinetic heating may be within reach of forthcoming infrared telescopes [18,19]. Provided NSs are nearby, faint and sufficiently isolated, they are likely to be discovered by existing radio telescopes such as the Fivehundred-meter Aperture Spherical radio Telescope (FAST) [37], or the future Square Kilometer Array (SKA) [38]. Their thermal emission can then be m...

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Section: Introductionmentioning

confidence: 99%

Capture of leptophilic dark matter in neutron stars

Bell

Busoni

Robles

2019

J. Cosmol. Astropart. Phys.

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“…One of the most exciting environmental effects would be from the dark matter (DM). For example, DM can accumulate at the core of NS, strongly modifying NS binary mergers [6][7][8][9]. A DM locus nearby the binary may be also able to perturb the binary orbit in such a way to enhance the instability or ellipticity [10].…”

Section: Introductionmentioning

confidence: 99%

New probe of dark matter-induced fifth force with neutron star inspirals

Choi

Jung

2019

Phys. Rev. D

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A light scalar dark matter (DM) is allowed in a wide range of its mass and interaction types. We show that the light scalar DM may be probed in a new way from final years of neutron-star (NS) binary inspirals. If the DM interacts with the neutron, its long wave coherence in the background can induce the time-oscillating mass shift, to which the binary inspiral is inherently sensitive. But the sensitivity is found to be significantly enhanced by a large number of gravitational-wave (GW) cycles during year-long highest-frequency measurements in the broadband f 0.01 − 1000 Hz. Such broadband measurements that can be realized by a future detector network including LIGO and mid-band detectors can probe unconstrained parameter space of the light scalar DM.

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“…II), but also the conditions for self gravitation and more importantly on the condition for BEC formation, see Eqs. (53) and (64), respectively. As for the local DM density we assume that it has not changed significantly during the evolution of NS.…”

Section: Exclusion Curves For Old Neutron Starsmentioning

confidence: 99%

“…As noted already, BH formation in this case is governed by the self gravitation condition of Eq. (53). For masses smaller than ∼ 100 MeV, for a given cross section, DM accretion is inefficient and can never accrete enough DM particles such that they self gravitate.…”

Section: Exclusion Curves For Old Neutron Starsmentioning

confidence: 99%

“…(10) for ρ χ = 10 4 GeV/cm 3 ). However one could eventually get more DM in other ways [53][54][55][56]. In this case one could hope, see for instance [57], that during the final stage of the spiral motion, because of tidal forces, the two DM cores come out of the neutron stars and continue to rotate within the newly-formed matter disk.…”

Section: Appendix G: Remark Regarding the Effect Of Dm On Gravitationmentioning

confidence: 99%

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New analysis of neutron star constraints on asymmetric dark matter

Garani

Génolini

Hambye

2019

J. Cosmol. Astropart. Phys.

102

165

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Due to their extreme density and low temperature, neutron stars (NS) are efficient probes to unveil interactions between standard model and dark matter (DM) particles. From elastic scatterings on NS material, DM can get gravitationally trapped by the star. The cooling of DM through further collisions may lead to the formation of a dense core which could collapse into a black hole, thus destroying the whole NS. From the observation of old NS, such a scenario leads to very stringent constraints on the parameter space of asymmetric DM. In this work we reexamine this possibility in detail. This includes: (a) a new detailed determination of the number of DM particles captured, properly taking into account the fact that neutrons form a highly degenerate Fermi material; (b) the determination of the time evolution of the DM density and energy profiles inside the NS, which allows us to understand how, as a function of time, DM thermalizes with NS material; (c) the determination of the corresponding constraints which hold on the DM-neutron cross section, including for the case where a large fraction of DM particles have not thermalized; (d) the first determination of the stringent constraints which also hold in a similar way on the DM-muon cross section, particularly relevant for leptophilic DM models; and (e) the use of realistic NS equations of state in determining these constraints. * Electronic address: rgaranir@ulb.ac.be † Electronic address: yoann.genolini@ulb.ac.be ‡ Electronic address: thambye@ulb.ac.be arXiv:1812.08773v1 [hep-ph] Note that small momentum dependence in the cross section has been ignored. For scalar interactions, i.e. L int ⊃the cross sections are dσ χ−f d cos θcm = G 2 S 8π m 2 f (mχ+m f ) 2 and dσ χ−f d cos θcm = G 2 S 2π m 2 χ m 2 f (mχ+m f ) 2 ,

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Dark halos around neutron stars and gravitational waves

Cited by 104 publications

References 67 publications

Capture of leptophilic dark matter in neutron stars

Capture of leptophilic dark matter in neutron stars

New probe of dark matter-induced fifth force with neutron star inspirals

New analysis of neutron star constraints on asymmetric dark matter

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